Pioneer Electronic Corporation

Pioneer Video Corporation

Osamu Kumasaka

Minemasa Ota

Nobuki Yamaoka

Teruo Touma

Katsura Ito

Kenji Koushiro

Hirotoshi Tabuchi

A method for preparing a stamper comprises the steps of forming a first electro-conductive layer and a second electro-conductive layer on a photoresist layer carrying pits through a physical vapor deposition before the electroforming of a stamper layer. The second electro-conductive layer is effective for preventing the first electro-conductive layer from corroding during the electroforming step because of the active treatment solution for the electroforming and also avoids the corrosion of the first electro-conductive layer even in the storage period before the particular electroforming step.

Method of manufacturing a stamper for formation of optical information

There is disclosed a method of identifying a stamper for an optical information storage disk in order to distinguish first and second stampers from each other, the second stamper being replicated from the first stamper, each of the first and second stampers carrying recorded information signals and a printed code pattern recorded circumferentially and representing stamper identifying information from each other. The printed code pattern is read in a predetermined direction, and it is determined whether a start or stop signal of the printed code pattern is read first. The first and the second stampers are distinguished from each other in dependence on whether the start or stop signal is read first.

Method of identifying stamper for optical information storage disk

A method and implementing apparatus for electroless plating an optical disk causes the disk to be positioned in a container with its main surface upturned and then rotated. As the disk rotates, liquid for treating or cleaning the disk is caused to fall on the upturned main surface from a position above the disk.

Electroless plating method and apparatus

A method for manufacturing an optical disk having both address pits and guide grooves having accurately controlled depths and widths. Two different types of sensitive materials of different characteristics are applied to a recording original board to form inner and outer layers thereon. The inner and outer layers are exposed and partially removed independently of each other so that the depth and width of the guide grooves and address pits can be set to desired values with high accuracy.

Method for manufacturing optical disk with address and guide grooves

An optical data recording disc has a protrusion forming layer which is formed on a gas generating metal layer, and the gas generating metal layer, in turn, is formed on an optically polished disc. An optical beam is modulated by data and impinges on the gas generating metal layer, which locally evaporates the metal layer to form a gas. The gas expands and produces protrusions in the protrusion forming layer, and these protrusions are representative of the data. Accordingly, because the protrusions are formed essentially simultaneously with the recording operation, it is possible to reproduce the data being recorded immediately after the data is recorded so that failures in a recording device or in the optical data recording disc can be detected immediately.

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Yamanashi, Japan

Osamu Kumasaka